The present invention relates generally to the field of mail extraction, and in particular, to certain improvements in mail extraction devices which make use of opposing suction cups to engage and spread apart envelope faces to gain access to contents of the envelope.
A variety of devices have been developed to facilitate the mail extraction process, in which large quantities of envelopes are automatically opened to gain access to their contents. One example of this is the "Rapid Extraction Desk" manufactured by Opex Corporation of Moorestown, N.J., an exemplary model of which is illustrated in U.S. Pat. No. 3,979,884 (Re 32,328).
In their overall operation, these machines are used to receive a series of envelopes which are first sequentially delivered to a device for severing (cutting open) one or more envelope edges, and which are then sequentially delivered to an extraction area for access by the machine's operator. At the extraction area, steps are taken to spread apart the opposing faces of the envelope, permitting the operator to gain access to the contents of each envelope for extraction. The emptied envelope is then released from the extraction area, and is preferably then checked to make sure that the envelope has been emptied of all of its contents.
Although other approaches have been used (such as the early "vacuum box" systems which were marketed by the Bell and Howell Company), a preferred means for spreading open the opposing faces of an envelope involves the use of opposing suction cups mounted to a pair of arms which are movable toward and away from the envelope to be opened, in controlled fashion. This approach has been found to be beneficial in ensuring that each of the series of envelopes to be opened is effectively engaged (and opened) at the operator's extraction station. This is because reciprocating suction cups can operate to positively engage the opposing faces of the envelope resulting from their direct contact with the envelope's faces.
While this approach operates to ensure that each envelope is effectively spread apart at the operator's extraction station, this has also been found to at times contribute to a condition known as "bleed through", which causes contents of the envelope to stick to the inside of one or the other of the envelope's faces. This is because following contact of the opposing suction cups with the envelope's faces, the applied vacuum can at times bleed through the somewhat porous paper which forms the envelope, also entraining contents of the envelope. This can be troublesome in that the operator is then presented with a certain degree of difficulty in separating the entrained contents from the opened envelope, either slowing the extraction process, or at times causing a document to be missed entirely.
Recognizing this problem, efforts have been made to overcome the adverse affects of bleed through. One such approach is disclosed in U.S. Pat. No. 4,110,958. Described is a configured suction cup having a contoured face which imparts a localized curvature to the engaged face of the envelope to create a space between the engaged face of the envelope and any document which might have become stuck to it. This then provides an open area which permits the operator to readily detect, and grasp the contents of the opened envelope, overcoming the disadvantages of bleed through. Yet another approach is disclosed in U.S. Pat. No. 4,388,793. Described is a mechanism which, in addition to spreading apart the opposing faces of an envelope, also produces a lateral shift of the respective faces relative to one another, to once gain create a localized curvature which operates to separate documents contained by the envelope from the adjacent envelope faces. However, the former approach has proved to be somewhat less than satisfactory, and the latter approach requires a relatively complicated mechanism to achieve its end result.
It therefore became desirable to develop a more effective means for overcoming the disadvantages of bleed through, to further facilitate the extraction of contents from their respective envelopes.